不同类型土壤栽培对苦丁茶树叶片生长和光合特性的影响

研究苦丁茶树叶片生长与光合特性对不同类型土壤栽培的响应特征,确定最适苦丁茶栽培的土壤类型,可为高产优质化的苦丁茶种植业及其规模化生产基地的建立提供科学依据。通过土壤栽培实验研究了不同类型的土壤对苦丁茶树叶片生长、叶片解剖结构、叶绿素含量和光合特性的影响。结果表明:石灰岩土壤栽培条件下,苦丁茶叶长和叶面积比其他6种土壤栽培下的显著提高了34%—57%和43%—68%,叶绿素总量显著增加9%—33%,叶片、上下表皮、海绵组织和栅栏组织的厚度均显著高于其他6种土壤栽培。不同类型土壤栽培下苦丁茶净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和饱和蒸气压亏缺(Vpdl)的日变化趋势均呈单峰型,日均Pn和Tr值大小依次为:石灰岩石英砂岩玄武岩长石石英砂岩第四纪红色黏土变余砂岩煤系砂页岩,其中石灰岩土壤栽培下的日均Pn值相比其他6种土壤下的显著提高了13%—45%,且叶片最大净光合速率、表观量子效率、暗呼吸速率、光补偿点(LCP)和光饱和点(LSP)也最大,而煤系砂页岩栽培时最低,其LSP和LCP较石灰岩栽培的分别显著下降了40%和46%。综上,在7种类型的土壤中,石灰岩土壤栽培最有利于苦丁茶树叶片的生长发育、并促进叶绿素的合成和加强对光能的吸收利用,最终提高其叶片光合能力,其次为玄武岩土壤,而煤系砂页岩土壤是最不利于苦丁茶树叶片生长发育和光合作用。建议在苦丁茶种植业的发展和规模化生产基地建立时因选择由石灰岩性母岩发育的土壤进行栽培,从而提高苦丁茶的产量和品质。

Effects of different soil types on growth and photosynthetic characteristics of Ligustrum robustum

In this study, we investigated the effects of seven types of cultivation soil on leaf growth and photosynthetic characteristics of Ligustrum robustum (kuding tea) seedlings, aiming to provide scientific advices for cultivation and management of the species for cultivation and management of the species. We measured leaf length, width, area, spongy tissue thickness, palisade tissue thickness, layer of palisade tissue, chlorophyll content, and photosynthetic parameters of the seedlings grown in different soil types. The results showed that cultivation in limestone soil increased the length and area of the leaves by 34%-57% and 43%-68%, respectively, when compared with the other six soil types. In addition, leaf thickness, spongy tissue, and palisade tissue were significantly higher, and total chlorophyll content was 9%-33% higher in the limestone soil than in the other six soil types. The soil types did not affect the diurnal variation in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and vapor pressure deficit (Vpdl). The daily average of Pn and Tr values in the seven soil types in descending order were as follows:limestone > quartz sandstone > basalt > feldspathic quartz sandstone > quaternary red clay > blastopsammite > coal sand shale. The daily average of Pn value was 13%-45% higher in limestone soil than in the other six soil types. Pn, Gs, and Tr were positively correlated, but they were negatively correlated with Vpdl. The maximum net photosynthetic rate, light saturation (LSP), light compensation (LCP), dark respiration rate, and apparent quantum yield were observed in limestone soil. LSP and LCP were significantly lower in coal sand shale soil (40% and 46%, respectively) than in the limestone soil. In summary, limestone soil is most beneficial for the growth and development of leaves. It can promote the production of chlorophyll and thus enhance the absorption and utilization of light energy and improve leaf growth and photosynthetic capacity. The second appropriate soil type is basalt. In contrast, coal sand shale soil is most unfavorable for the growth and development of leaves and photosynthesis. Therefore, limestone soil should be used for the large-scale plantation of L. robustum and improvement of the yield and quality of kuding tea.